Fair note: A lot of these comments are under the assumption you are using the os_prober feature in grub to detect the windows install. While this is usually the case, if you have ever supplied a manual entry for windows in /etc/grub.d to specify where your windows install is (I was forced to do this because os_prober refused to see my windows system after recreating my EFI partition), you will need to delete that entry again in order for the windows option to disappear on grub.
It would still boot your Linux mint, but you would have a windows entry in the boot menu that didn't go anywhere.